In the manufacture of circuit boards and thin film polyimide laminate assemblies, it is often necessary to fabricate small via holes. The vias are used to connect top, bottom and intermediate circuity layers. The present process for creating these small holes requires from eight to ten, one inch square electromagnetic repulsion drive coils that propel a punch through the polyimide material layers. The coils are individually screw fastened to diebars, which provide proper alignment for the holes.
The process is tedious and time consuming. Each job requires different part spacings and frequent maintenance dictated by having to clean each coil.
The present invention features a coil holding block that holds a column of individual coils. The holding block acts as a single unit, and is magnetically attached to a punch diebar. The magnetic attraction between the holding block and die bar provides easy assembly and disassembly of the parts. The magnetic assembly reduces the replacement time for the coils from a previous forty-five minutes to less than one minute.
Milled pockets in a lower portion of the holding block provide proper static punch height. In the previous assembly, such spacing had to be individually aligned by hand under each coil. Thus, the coil block holder of this invention eliminates the requirement for individual spacers, tedious spacer/coil alignment, and the screw unfastening of the coils.